310 



CYPERACEAE. 



VOL. I. 



37. Cyperus globulosus Aubl. Baldwin's Cy- 

 perus. Fig. 757. 



C. globulosus Aubl. PI. Guian. I : 47. 1775. 

 Mariscus echinatus Ell. Dot. S. C. & Ga. I : 75. 1816. 

 Cyperus Baldwinii Torr. Ann. Lye. N. Y. 3 : 270. 1836. 

 Cyperus echinatus Wood, Class-book 734. 1863. 



Perennial by tuber-like corms, culm slender, smooth, 

 erect, mostly longer than the leaves. Leaves pale 

 green, \\"-2." wide, those of the involucre 5-10, the 

 longer usually much exceeding the umbel ; umbel 

 simple, 6-i3-rayed, the rays filiform, their sheaths 

 short, mucronate; spikelets 2."-$" long, linear, flat, 

 densely or loosely capitate in globose heads; scales thin, 

 pale green, appressed, ovate-lanceolate, acute, 9-13- 

 nerved, with narrow scarious margins; joints of the 

 rachis broadly winged; stamens 3; style 3-cleft; achene 

 oblong-obovoid, obtuse, one-half as long as the scale, 

 about twice as long as thick. 



In dry soil, sometimes a weed in cultivated fields, Vir- 

 ginia to Florida, west to Missouri and Texas. Also in Ber- 

 muda and in tropical America. July-Aug. 



3. ELEOCHARIS R. Br. Prodr. Fl. Nov. Holl. i : 224. 1810. 



Annual or perennial sedges. Culms simple, triangular, quadrangular, terete, flattened or 

 grooved, the leaves reduced to sheaths or the lowest very rarely blade-bearing. Spikelets 

 solitary, terminal, erect, several-many-flowered, not subtended by an involucre. Scales con- 

 cave, spirally imbricated all around. Perianth of 1-12 bristles, usually retrorsely barbed, 

 wanting in some species. Stamens 2-3. Style 2-cleft and achene lenticular or biconvex, or 

 3-cleft and achene 3-angled, but sometimes with very obtuse angles and appearing turgid. 

 Base of the style persistent on the summit of the achene, forming a terminal tubercle. 

 [Greek, referring to the growth of most of the species in marshy ground.] 



About 140 species, widely distributed. Besides the following, some 20 others occur in *he 

 southern and western parts of North America. Type species : Scirpus palustris L. 



i. Spikelet scarcely or not at all thicker than the culm; scales coriaceous. 

 Culm stout ; spikelet many-flowered. 



Culm terete, nodose. i. E. interstincta. 



Culm quadrangular, continuous. 2. E. mutata. 



Culm slender, triangular, continuous ; spikelet few-flowered, subulate. 3. E. Robbinsli. 



2. Spikelet manifestly thicker than the culm (except in No. 13); scales membranous. 

 *StyIe mostly 2-cleft ; achene lenticular or biconvex. 



Upper sheath scarious, hyaline ; plants perennial by slender rootstocks. 

 Scales pale green or nearly white; achene l /\" long. 

 Scales dark reddish-brown ; achene y 2 " long. 

 Upper sheath truncate, oblique or toothed, not scarious. 

 Annual, with fibrous roots. 

 Achene jet black. 



Culms i '-3' tall ; achene y\" long; bristles 2-4. 

 Culms 3'-io' tall; achene Y^" long; bristles 5-8. 

 Achene pale brown. 



Spikelet ovoid or oblong. 



Tubercle narrower than the top of the achene. 

 Tubercle about as broad as the top of the achene. 

 Spikelet oblong-cylindric ; tubercle broad, low. 

 Perennial by horizontal rootstocks. 

 Scales pale green to straw-color. 

 Scales brown to purple-brown. 



Tubercle flattened-conic ; spikelet thicker than the culm. 



Tubercle swollen, bulb-like ; spikelet not thicker than the culm. 13. E.Smallii. 

 **Sty!e 3-cleft ; achene 3-angled or turgid. 

 Achene reticulated or cancellate. 



Spikelet compressed ; culm filiform. 

 Spikelet terete ; culm slender. 



Achene transversely cancellate ; bristles none. 

 Achene reticulated ; bristles present, stout. 

 Tubercle conic, smaller than the achene. 

 Tubercle cap-like, as large as or larger than the achene. 

 Achene smooth or papillose. 



Achene smooth, white ; culms capillary. 

 Achene papillose or smooth, brown, black or yellow. 

 Tubercle depressed or short-conic. 

 Achene smooth. 



Tubercle flat, covering the top of the black achene. 

 Tubercle ovoid-conic, acute, contracted at the base. 

 Achene papillose. 



Achene 3-ribbed on the angles. 

 Achene obtuse-angled, not ribbed. 



4. E. flaccida. 



5. E. olivacea. 



6. E. atropurpurea. 



7. E. capitata. 



8. E. ovata. 



9. E. obtusa. 



10. E. Engelmanni. 



11. E. macrostachya. 



1 2. E. palustris. 



14. E. acicularis. 



15. E.Wolfii. 



1 6. E. simplex. 



17. E. tuberculosa. 



1 8. E. Torreyana. 



19. E. melanocarpa. 



20. E. albida. 



21. E. tricostata. 



